Figure 1.

Direct and receptor-dependent stimulation of AC increases the intracellular cyclic AMP in skeletal muscle cells. Rat cultured skeletal muscle cells, pre-incubated with 1 mM IBMX, were treated with 3–100 nM CGRP, 0.1–100 μM isoprenaine, 1–100 μM forskolin or vehicle, for 10 min at 37°C. The cyclic AMP was measured using a cyclic AMP [³H]-assay kit and expressed as percentage of the basal values (100%). Each point represents the mean±s.e.mean; n=3–4.